Microsoft recommends enabling automatic updates to ensure an up-to-date computing experience—including the latest version of Internet Explorer—and most consumers use automatic updates today. Commercial customers are encouraged to test and accept updates quickly, especially security updates. Regular updates provide significant benefits, such as decreased security risk and increased reliability, and Windows Update can automatically install updates for Internet Explorer and Windows.
After January 12, 2016, only the most recent version of Internet Explorer available for a supported operating system will receive technical support and security updates. For example, customers using Internet Explorer 8, Internet Explorer 9, or Internet Explorer 10 on Windows 7 SP1 should migrate to Internet Explorer 11 to continue receiving security updates and technical support. For more details regarding support timelines on Windows and Windows Embedded, see the Microsoft Support Lifecycle site.
As some commercial customers have standardized on earlier versions of Internet Explorer, Microsoft is introducing new features and resources to help customers upgrade and stay current on the latest browser. Customers should plan for upgrading to modern standards—to benefit from the additional performance, security, and productivity of modern Web apps—but in the short term, backward compatibility with legacy Web apps may be a cost-effective, if temporary, path. Enterprise Mode for Internet Explorer 11, released in April 2014, offers enhanced backward compatibility and enables you to run many legacy Web apps during your transition to modern Web standards.
via Stay up-to-date with Internet Explorer – IEBlog – Site Home – MSDN Blogs.
Even though January 2016 may seem like the distant future, it’ll be here before you know it. If your still using apps that rely on IE 8 or 9 you’d better get those upgraded or risk running into issues later.